The metabolism of the corticosteroid side-chain is being studied in man and animals. This is accomplished by utilizing corticosteroids labeled with tritium at position 21 and C14 at position 4 (corticosteroid-4-C14-21-H3). The objectives are to determine the significance of a pathway of degradation which lead to the formation of steroidal carboxylic acids and to the loss of tritium of the methylol group.